1. Field of the Invention
The present invention relates generally to a mobile communication terminal capable of performing communication (TRS communication) using a Trunked Radio System (TRS), and more particularly to a method for efficiently performing mobile communication and TRS communication.
2. Description of the Related Art
TRS communication is characterized in that it calls unspecified persons while continuously opening a specific channel. That is, in TRS communication, a plurality of channels may be selected and unspecified persons are called for each selected channel. In order to perform TRS communication in a mobile communication terminal, it is necessary to always connect to a channel used in TRS communication, i.e., a TRS channel, and respond to signals received from unspecified persons, while holding a mobile communication channel. Therefore, when another channel is used in TRS communication, inefficiency and power waste due to TRS channel searching may occur.
Further, even though a TRS channel is fixed, inefficiency may occur because all messages from unspecified persons must be processed. Power waste is a very important issue in the use of a mobile communication terminal. Accordingly, it is necessary to provide a method capable of efficiently searching for a channel between mobile communication and TRS communication, and efficiently searching and managing other channels also in a single mode for TRS communication, in order to prevent power waste.
In order for a conventional mobile communication terminal capable of performing TRS communication, i.e., a TRS mobile communication terminal, to enter a mode used for TRS communication, i.e., a TRS communication mode, a mode and a channel must be manually changed by a user. In setting a channel, there is an inconvenience in that users must define a channel in advance and set the TRS channel.
Further, in order for a plurality of designed groups to communicate with a plurality of channels by radio, communication with all groups is not performed, rather only a designed group is selected and a channel is fixed. Therefore, an inconvenience may occur.
Furthermore, there is an inconvenience in that it is necessary to respond to calls of undesired, unspecified persons also over the same TRS channel.
Moreover, all users using the same TRS channel may be interfered by unspecified persons in the same area.
A user may use a plurality of TRS channels to communicate with a plurality of groups, but the user must fix a corresponding TRS channel in order to communicate with a desired group. Further, the user must perform a channel change in order to communicate with another group in the TRS channel, such that it is impossible to have a correlation with the TRS channel currently in communication.
Furthermore, because all users using the same TRS channel continuously receive calls from unspecified persons in the same area, battery waste often occurs.